Gwendolyn "Gwen" Catherine Tennyson is a Human/Anodite hybrid Plumber, the paternal first-cousin of Ben Tennyson, and (along with Kevin Levin) a frontline member of his team. Gwen was first introduced when her parents sent her on a summer-long road trip with her Grandpa Max and her cousin Ben. She has, as Verdona refers to it, "The Spark".
|Gwendolyn Catherine Tennyson|
|Age||10 (Ben 10)|
11 (Omniverse Flashbacks)
15 (Alien Force)
16 (Ultimate Alien and Omniverse)
11th grade StudentPlumber
|Powers and abilities|
Charms of Bezel(Formerly) Spell Book
Lovely/Sweet Gwen (Michael Morningstar/Darkstar and Ultimate Kevin)
Gwenny (Zombozo and Natalie)
Big Butt (Ben)
Little Lady (Morgg)
Little Sucker (Hex)
My girl (Ultimate Kevin)
Miss Perfect Princess (Sunny)
Sorceress (Sir Cyrus in The Creature From Beyond)
Genevieve (French teacher)
Idiot Savant (Charmcaster)
My favourite grandchild (Verdona)
Red (Ben 10,000 and Argit)
The Witch (Sir Driscoll in A Knight To Remember
|Alternate Counterparts||Gwen at Gwen 10
Gwen at Ben 10,000 and Ken 10
|Voice Actor||Meagan Smith (Ben 10)|
Ashley Johnson (Alien Force, Ultimate Alien, Ben 10: Omniverse)
Haley Ramm (Ben 10: Race Against Time)
Galadriel Stineman (Ben 10: Alien Swarm)
|First Appearance||And Then There Were Ten|
In Omniverse, 16 year old Gwen still has her ponytail but with a different style. She now wears clothes similar to her Alien Force outfit minus the leggings. She also now has freckles.Later on she has shorter hair, a light blue shirt with her cat logo on her shirt, a blue skirt and wears glasses. 11 year old Gwen in Omniverse wears the same outfit from the original series she has not changed much.
16 year-old Gwen
- The More Things Change: Part 1 (first appearance)
- Many Happy Returns
- Ben Again
- Showdown: Part 2
- The Frogs of War: Part 2
- Mud is Thicker Than Water
- For a Few Brains More
- A Jolt from the Past
- Trouble Helix
- It Was Them (cameo)
- Of Predators and Prey: Part 2
- Ben Again
- Mud is Thicker than Water (flashback)
- Gwen and Kevin will leave for college in Ben 10: Omniverse.
- Gwen and Kevin will still remain in a relationship.
- Gwen wears her Alien Force outfit in Omniverse.
- Gwen's new look resembles Velma Dinkley from the Scooby Doo series.